Fan blades

John Massengale · Post by **John Massengale** » Thu Jan 23, 2003 6:14 pm

I think i read somewhere that the cooling fan on a stock cooled type 4 engine can cool better by breaking off every 5th blade or something. is this true, or should I leave them all in? Thanks, John

TwoLiter · Post by **TwoLiter** » Thu Jan 23, 2003 6:22 pm

The fan is balanced at the factory, and breaking off blades will most likely throw it off balance. I don't think that is a good thing.

John Massengale · Post by **John Massengale** » Thu Jan 23, 2003 8:56 pm

Yes yur right, my teacher says it probobly isn't a good idea either, But still don't know if makes it blow more air, John

johnhora · Post by **johnhora** » Thu Jan 23, 2003 8:57 pm

John...You've got too much time on your hands...no classes eh..

What you probably have heard was that some racers in the past have removed all blades except the main bolt points. This is done to reduce the fan drag on the engine. This was only done with an external oil cooler and usually some major ducting of air to the fan intake area.

Bottom line you don't want to do it. Especially on a street car....a constantly moving racer car was different.

And as above...the fan is balanced like a flywheel.

John

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Fri Jan 24, 2003 9:22 am

I sometimes remove evey other balade in the mill, and then rebalance the fan assembly to match..

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Jake Raby
Raby's Aircooled Technology
www.aircooledtechnology.com

Dave_Darling · Post by **Dave_Darling** » Fri Jan 24, 2003 10:13 am

I have read that the stock fan becomes more inefficient at high RPMs, and that removing some of the fan blades regains some of that efficiency. But that it cools worse at lower RPMs, which is where a street car spends most of its life. (Well, except for Jake's cars--but he's a special case!

)

And the fan is always balanced afterwards, both on its own and then as a part of the rotating assembly of the engine.

--DD

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1974 VW-Porsche 914 2.0 (Type IV powered!)

Pelican Parts' 914 Tech Geek http://www.pelicanparts.com

John Massengale · Post by **John Massengale** » Fri Jan 24, 2003 3:11 pm

Thanks, Guys, I will leave them the way they are, John

flat4-4now · Post by **flat4-4now** » Sat Jan 25, 2003 10:40 pm

my fan blade has 2 missing fins, both side by side. should i replace it or just have it balanced with everything else and go?

Is the t4 fan blade the same as the bus? and if so, what do new ones cost (PP=250.00)? I guess a decent used one would work...

[This message has been edited by flat4-4now (edited 01-25-2003).]

Zeke · Post by **Zeke** » Sun Jan 26, 2003 8:51 am

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by flat4-4now:
<B>my fan blade has 2 missing fins, both side by side. should i replace it or just have it balanced with everything else and go?

Is the t4 fan blade the same as the bus? and if so, what do new ones cost (PP=250.00)? I guess a decent used one would work...

[This message has been edited by flat4-4now (edited 01-25-2003).]</B><HR></BLOCKQUOTE>
I would look for another fan. Around here, they cost $20 used. If you know what you are doing, you can remove corresponding fins in a triangular pattern. I can tell you that in that respect, I don't know what I'm doing.

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Milt
914 2.0-4 Race Car w/ 2.7-6 in waiting.